Transverse Problems

Question 1

what is the prevalence of anterior crossbites

Answer 1

2.2%-11.9%

Question 2

when is the anterior crossbite manifested

Answer 2

in the mixed dentition

Question 3

what is the result of no tx of an anterior crossbite

Answer 3

• esthetic problem
• damage to the teeth in crossbite through attrition
• gingival recession
• loss of alveolar bone on lower incisors
• excess mobility of lower incisors affected by the crossbite

Question 4

what is the DDX for anterior crossbite

Answer 4

• cepahlometric evaluation
• dental assessment: class III molar relationship
• negative overjet or end to end relationship with retroclined mandibular incisors (compensated class III malocclusion)
• if negative overjet, proceed to functional assessment
• functional assessment: determine whether a centric relation/centric occlusion discrepancy exists

Question 5

what might an anterior crossbite DDX patient have in the functional assessment of CR and CO

Answer 5

• at CR, patient may have a class I skeletal pattern, normal facial profile and class I molar relationship
• at CO, patient may have a class III skeletal and dental pattern

Question 6

what is examined in the DDX for anterior crossbite

Answer 6

• cephalometric evaluation
• dental assessment
• functional assessment
• profile analysis

Question 7

if the pt has a class III molar relationship with negative overjet what do you need to do

Answer 7

a functional assessment- see if there is a CR CO discrepancy
- if no CR CO discrepancy -> true class III malocclusion
- if there is a CR-CO shift -> pseudo class III maloclussion

Question 8

what do you do if a pt is in a pseudo class III relationship

Answer 8

eliminate CR CO shift

Question 9

what happens if you eliminate a CR CO shift in pseudo class III

Answer 9

you get a class I molar relationship -> class I malocclusion or a class III molar and you get a compensated class III malocclusion

Question 10

what is a class III molar with positive overjet and retroclined mandibular incisors

Answer 10

compensated class III malocclusion

Question 11

in an anterior cross bite what should the ceph show you in the skeletal

Answer 11

class III maxillo mandidular relationships

Question 12

in an anterior cross bite what would the ceph show you in the dental

Answer 12

class I or II maxillo-mandibular relationships

Question 13

in an anterior crossbite what would the dental eval show you about the skeletal

Answer 13

• severe proclination of upper incisors
• severe retroclination of lower incisors
• class III molar relationships
• may or may not be present in class III skeletal

Question 14

in an anterior crossbite what would the dental exam show you about dental relationship

Answer 14

• normal inclination/position or severe retroclination/retrusion of upper incisors
• severe proclination/protrusion of lower incisors
• class I or II molar relationship
• presence of anterior functional shift
• may or may not be present in class III dental

Question 15

what would the profile exam tell you about the skeletal relationship in an anterior crossbite

Answer 15

concave or straight
- may or may not be present in class III skeletal

Question 16

what would the profile exam tell you about the dental in an anterior crossbite

Answer 16

straight or convex

Question 17

what is the most common etiologic factor for nonskeletal anterior crossbites

Answer 17

lack of space for the permanent incisors

Question 18

what should the tx plan be focused on for the early treatment of dental anterior crossbite

Answer 18

on management of the total space situation, not just the crossbite

Question 19

what is the management of early tx of dental anterior crossbite

Answer 19

• extraction of adjacent primary teeth to provide necessary space
• disking of teeth
• opening space for tooth movement
• determine whether tipping will provide appropriate correction

Question 20

what are the treatment modalities for anterior crossbite

Answer 20

• fixed inclined planes
• reverse crown
• maxillary lingual holding arch with springs
• removable appliance with jackscrew
• 2x4 appliance

Question 21

what is a reverse crown

Answer 21

a large permanent anterior tooth crown is reverse cemented

Question 22

what is the purpose of a maxillary lingual holding arch with springs

Answer 22

lingual eruption of maxillary lateral incisors in a crowded arch

Question 23

what should the general dentist do for an anterior crossbite

Answer 23

refer to orthodontist

Question 24

what is the objective of anterior crossbite tx

Answer 24

reduce the amount of dental compensation to skeletal; discrepancy that are often associated with a more severe malocclusion in late adolescence

Question 25

where are abutments for the 2x4 appliance placed

Answer 25

on first molars and maxillary incisors

Question 26

what is the prevalence of the posterior crossbite

Answer 26

- 7.3% of hispanic population - 9.6% in african american populations - 9.1% among caucasians

Question 27

what is a cause of the posterior crossbite and what is it

Answer 27

- transverse maxillary deficiency: narrow maxilla relative to the rest of the face

Question 28

what happens in the hidden posterior crossbite

Answer 28

- compensatory changes in dentoalveolar processes - tipping of maxillary teeth to the buccal - tipping of mandibular teeth to the lingual - uprighting teeth creates a dental crossbite

Question 29

a unilateral posterior crossbite may be:

Answer 29

a bilateral crossbite with a functional lateral jaw shift as the teeth from centric relation to centric occlusion

Question 30

what is the key sign of unilateral posterior crossbites

Answer 30

- deviation of the mandibular dental midline, relative to the maxillary dental and skeletal midlines, toward the side of the crossbite when the teeth are in MI

Question 31

what are the sequelae to posterior crossbites due to functional shifts not being treated

Answer 31

- compensatory changes in the TMJ - no strong evidence - modifications of soft tissue growth - no strong evidence - development of skeletal asymmetries - no strong evidence - attrition of teeth

Question 32

do posterior crossbites due to functional shifts self correct

Answer 32

no

Question 33

what needs to be considered for posterior crossbite management?

Answer 33

- is the crossbite skeletal or dental - is the crossbite unilateral or bilateral - is there a functional shift - if dental, which teeth are tipped and in which jaws - should the treatment be initated at this time or deferred to a later date - should the problems be corrected - can the problem be corrected or masked by treatment

Question 34

how is a posterior cross bite managed

Answer 34

- simple dentoalveolar unilateral posterior cross bite: fixed or removable appliances to move teeth - W-arch, quadhelix - jackscrew

Question 35

what ages do you use the W-arch, quadhelix for

Answer 35

up to age 9 or 10

Question 36

what does the jackscrew do for the posterior cross bite

Answer 36

relatively heavy force that separates the partially interlocked suture

Question 37

where is the anchorage and rate of expansion for rapid palatal expansion

Answer 37

- posterior teeth - 0.5-1.0mm/day

Question 38

where is the anchorage and rate of expansion for slow palatal expansion

Answer 38

- posterior teeth - 1.0mm per week

Question 39

where is the anchorage and what is the rate of expansion for implant supported expansion

Answer 39

- maxilla- bone screws - slow or rapid

Question 40

what expansion do you use in the early mixed dentition

Answer 40

slow expansion

Question 41

suture can be separated in females up to age:

Answer 41

16

Question 42

suture can be separated in males up to age:

Answer 42

18

Question 43

what radiograph is used to assess the midpalatal suture patency

Answer 43

an occlusal radiograph

Question 44

what is another name for the buccal crossbite

Answer 44

scissor bite

Question 45

what is a scissor bite

Answer 45

buccal displacement of a maxillary posterior tooth, with or without contact between the lingual surface of the maxillary lingual cusp and the buccal surface of the mandibular antagonist's buccal cusp

Question 46

what is a complete buccal crossbite and what isa another name for it

Answer 46

- Brodie bite - a combination of excessive maxillary width and a narrow mandibular alveolar process, although the width of the mandibular base is usually normal

Question 47

what is a scissor bite treated with

Answer 47

- elastics - mandibular appliance to upright posterior teeth - lip bumber